While advances in medical care have reduced mortality rates across the globe, the same cannot be said for perinatal mortality. This is particularly true of Low and Middle Income Countries (LMICs), which contribute by far the largest proportion of the estimated 5.4 million perinatal deaths annually. Key reasons for this include lack of systematic screening, lack of early health advice-seeking, lack of training for the healthcare workers involved in the healthcare delivery chain and a lack of robust referral. To address these issues we propose to introduce and evaluate a scalable mHealth referral system in Guatemala, one of the poorest countries in Latin America with one of the highest perinatal mortality rates. The system combines several key innovations which have been developed over the last 10 years. First, we will introduce a low cost (under $30) ultrasound screening tool, with blood pressure cuff and pulse oximeter, from which data is fed directly to a smartphone to produce an on-the-spot assessment of the health of the fetus and mother, using a step-by-step pictorial guide (also on the phone). Second, we will implement a mobile phone- mediated medical record and referral system which allows users of both smartphones and basic mobile phones to upload data into a standardized medical record system already in operation in Guatemala. The data will allow healthcare workers to identify or enroll patients, review their histories, and schedule future screenings or follow-up visits, as well as equip the healthcare providers with the necessary information to assess needs, resource allocation and efficacy of treatment or personnel. Thirdly, we will introduce a training protocol for lay midwives to provide routine screening with our system for preeclampsia, intrauterine growth restriction and fetal distress, and to promote postnatal care coordination. Importantly, this shared system will facilitate communication between the obstetrical care team and the postnatal child care team, which currently represents one of the most pressing care coordination challenges in rural Guatemala. By bringing together engineers, physicians, public health workers, anthropologists, and local nongovernmental organizations to co-design the system around the needs of the existing healthcare infrastructure and the local population, we envision an intuitive system which relieves the burden of data collection, improves diagnostic capabilities, and assists with rapid and accurate referral. The system will also facilitate inter-facility research by introducing a unified medical record interchange protocol.